Rotary cutting tool, such as a drill, comprising an exchangeable cutting insert, and an exchangeable cutting insert

ABSTRACT

A tool shank for use with a cutting insert in a rotary cutting tool includes a body having, and adapted to be rotated about, a central longitudinal tool axis, the body having a tip portion structured to receive at least a portion of the cutting insert therein. The shank also includes a pair of chip flutes formed in the body and a pair of recesses, each recess bordering a respective chip flute. Each recess includes a rim portion extending perpendicular to the tool axis and a bearing surface extending at an incline relative to the tool axis. Each rim portion is adapted to engage a corresponding surface on the cutting insert. Each bearing surface is adapted to engage a corresponding bearing surface on the cutting insert in a manner such that the cutting insert is pulled against the body when the rotary cutting tool is rotated about the tool axis.

CONTINUING APPLICATION DATA

This application is a continuation of co-pending U.S. application Ser.No. 12/847,216, filed on Jul. 30, 2010, which is a continuation of U.S.application Ser. No. 12/047,904 (now U.S. Pat. No. 7,832,967), filed onMar. 13, 2008, which is a continuation of U.S. application Ser. No.10/921,781 (now U.S. Pat. No. 7,360,974), filed on Aug. 19, 2004, whichis a Continuation-In-Part application of International PatentApplication No. PCT/EP03/01526, filed on Feb. 15, 2003, which claimspriority from Federal Republic of Germany Patent Application No. 102 07257.4, filed on Feb. 21, 2002. International Patent Application No.PCT/EP03/01526 was pending as of the filing date of U.S. applicationSer. No. 10/921,781. The United States was an elected state inInternational Patent Application No. PCT/EP03/01526.

BACKGROUND

1. Field of the Invention

This application relates to a rotary cutting tool, especially a drillingtool, composed of a tool shank and an exchangeable cutting insert.

2. Background Information

A drilling tool comprising an exchangeable cutting insert is known fromEP 0 118 806 B 1, for example. Said drilling tool may have a tool shankwith an accommodation for inserting a fastening pin of the cuttinginsert. When the cutting insert is inserted, it may be rotated by anangle of approx. 45° relative to the tool shank. No other fasteningelement may be provided. The cutting insert and the tool body could beconfigured such that the shank-end narrow side of the cutting plate maybe braced against the shank-end rim of the recess in the tool shank. Anaxial force between the tool shank and the cutting insert can beproduced in that the shank-end rim of the recess may rise slightly inthe direction of insertion. The fastening pin can be secured againstbeing pulled out of the tool shank by means of a shank-end widening.This may cause bracing when the cutting insert is rotated into the seat,which may be intensified by cutting at higher cutting forces. The axialforce generated by such bracing may pull the cutting insert away fromthe tool body. The stability of the mount of the cutting insert on thetool shank and the mechanical load capacity of the drilling tool overallmay be restricted thereby.

According to another embodiment of the cutting tool known from EP 0 118806 B1, the fastening pin may be disposed concentrically on the cuttinginsert and may be provided with bearing surfaces rising slightlytwisting in the direction of the cutting rotation. By said slightlytwisting configuration of the bearing surfaces on the fastening pin,which can be in contact with correspondingly formed bearing surfaces onthe seat for the tool shank, an axial force may be applied on thecutting insert in the direction toward the tool body. Said axial forcemay act fully on the fastening pin, which may be small in size comparedto the tool diameter and thus may have a low mechanical load capacity.

Additionally, a torque may be applied to the fastening pin, which mayfurther reduce the mechanical load capacity of the connection betweenthe tool shank and the cutting insert.

OBJECT OR OBJECTS

One possible objective is to provide a rotary cutting tool composed of atool shank and a cutting insert with no other fastening elements,especially a drilling tool, where the connection between the tool shankand the cutting insert is especially stable and has a high loadcapacity.

SUMMARY

The problem may be solved in accordance with at least one possibleembodiment of the present application. The tool shank of a rotarycutting tool with an exchangeable cutting insert may be provided on thetool circumference with a limb that may be advantageously incliningoverall relative to the tool axis. A correspondingly inclining bearingsurface of a wing of the cutting insert can engage in said limb orguiding tab. When the cutting insert is rotated into the tool shank, theinclining bearing surfaces on the tool circumference may produce a forcethat could press the cutting insert against the tool shank. Said axialpressing force may increase when the tool is used at increasing cuttingforces. For transferring the torque between the cutting insert and thetool shank, the outside diameter region of the cutting insert or thetool shank, respectively, may be available. The arrangement of thebearing surfaces on the tool circumference may limit the forces requiredfor transferring the torque between the tool shank and the cuttinginsert to the lowest possible level.

The cutting insert may only partly cover the tool shank at the tip. Inparticular, the limb of the tool shank may not or may only partly becovered by the cutting insert at the tip. Therefore, the bearing surfaceof the cutting insert can extend virtually over its total height, exceptfor the fastening pin. This can ensure an especially large-surfacedforce and torque transfer between the cutting insert and the tool body.The limb provided for transferring the torque on the circumference ofthe tool body may advantageously extend virtually over the total heightof the wing of the cutting insert so that the wing could rise onlyslightly above the limb at the tip of the shank.

Advantageously, the diameter of the cutting element can be slightlygreater than the diameter of the tool shank, which may be a simplemethod to ensure that only the cutting insert will touch the surface ofthe work piece during machining.

When the cutting insert could be inserted in the tool shank, it mayinitially be inserted with the fastening pin in a location opening andthen rotated, similar to a bayonet joint. According to an advantageousfurther development to secure a defined axial position of the cuttinginsert relative to the tool shank after inserting the cutting insert andbefore rotating, both the tool shank and the cutting insert may beprovided with a guiding step.

The axial force pulling the cutting insert in the direction of the toolbody may be dependent upon the angle of contact of the bearing surfacesof the cutting insert and the tool shank relative to the tool axis. Bothan adequately high axial force and a stable design of the limb of thetool shank and the wing of the cutting insert may be advantageouslyobtained by an angle of contact of at least 15° and at most 60°,preferably 30°. In case the chucking groove or chip flute is twisted,the angle of contact advantageously may correspond to the angle of twistof the chucking groove.

The fastening pin and the corresponding accommodation in the tool shankmay be advantageously configured such that the fastening pin can bebraced when the cutting insert may be rotated into the tool shank. Tothis aim, the fastening pin may have an elliptical cross-section, whilethe location opening may have a circular cross-section. An ellipticalconfiguration of the fastening pin only may be advantageous in that inmanufacturing the tool, only one outside contour, namely on the cuttinginsert, may have to be elliptical, while an elliptical boring, whichcould be technically very difficult to do, may not be necessary.

Instead of a substantially cylindrical pin, possibly with a slightlyelliptical cross-section, the cutting insert can also have a pin inconical form. The accommodation of the tool shank, which may be conicalin this case, can have a circular cross-section slightly varying fromthe cross-section of the pin, which may also be advantageous with regardto manufacturing. The pin can taper conically downward, which could meantoward the tool shank, making it especially easy to insert the pin inthe tool shank, or alternatively, it may widen downward, which, combinedwith the elliptical cross-section may intensify the bracing of thecutting insert in the tool shank. Inserting and bracing the cuttinginsert in the tool shank may be easily possible in either case becausethe location opening of the tool shank could be open on the chuckinggrooves or chip flutes.

According to an advantageous further development, both the limb of thetool shank and the wing of the cutting insert may have a supplementalbearing surface in addition to the bearing surface, opposite the bearingsurface and inclined relative to the tool axis. Said supplementalbearing surfaces may advantageously join the bearing surfaces, and atransitional area that may be small relative to the bearing surfaces andthe supplemental bearing surfaces can be provided between said surfaces.If the bearing surfaces may be facing the tip of the tool and thesupplemental bearing surfaces may be facing the tool shank thetransitional area between the limbs and the adjacent region of the toolshank, which can be under particular mechanical stress when the tool isused as intended, could be specifically reinforced. Overall, the bearingsurfaces and supplemental bearing surfaces may form a large-surfacedarea of contact for transferring force and torque between the tool shankand the cutting insert. Both the bearing surfaces and the supplementalbearing surfaces can border on the tool circumference, except for anybeveled edges that may be provided on the individual surfaces, so thatwith regard to transferring the torque, the geometric conditions may beespecially favorable.

Similar to the bearing surfaces that advantageously could have an angleof contact between 15° and 60° relative to the tool axis, thesupplemental bearing surfaces may be advantageously inclined at asupplemental angle of contact between −10° and −60° relative to the toolaxis.

Advantageously, the supplemental bearing surfaces can be inclined by alesser angular amount than the bearing surfaces.

While the bearing surfaces generate an axial force that pulls thecutting insert toward the tool shank, the supplemental bearing surfacesmay produce an axial force in opposite direction. In order to ensurethat a resulting force holds the cutting insert against the tool shank,the so-called height of contact, relative to the tool axis, over whichthe bearing surface of the limb extends, advantageously may be greaterthan the so-called counter-height of contact over which the supplementalbearing surface of the limb extends. The equivalent may be true for thebearing surface and the supplemental bearing surface on the wing of thecutting insert. Therefore, the varying dimensions between the bearingsurfaces on the one hand and the supplemental bearing surfaces on theother hand could have the same effect as the variation in theinclination of the various surfaces, namely generating a resultingattracting force between the tool shank and the cutting insert when thetool may be in operation.

The above-discussed embodiments of the present invention will bedescribed further hereinbelow. When the word “invention” or “embodimentof the invention” is used in this specification, the word “invention” or“embodiment of the invention” includes “inventions” or “embodiments ofthe invention”, that is the plural of “invention” or “embodiment of theinvention”. By stating “invention” or “embodiment of the invention”, theApplicant does not in any way admit that the present application doesnot include more than one patentably and non-obviously distinctinvention, and maintains that this application may include more than onepatentably and non-obviously distinct invention. The Applicant herebyasserts that the disclosure of this application may include more thanone invention, and, in the event that there is more than one invention,that these inventions may be patentable and non-obvious one with respectto the other.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment is explained below in greater detail by means ofthe drawings, as follows:

FIG. 1 shows a rotary cutting tool composed of a tool shank and acutting insert;

FIG. 2 shows the tool shank of the rotary cutting tool of FIG. 1;

FIG. 3 shows the cutting insert of the rotary cutting tool of FIG. 1;

FIG. 4 shows the tool shank with the released fastening pin of thecutting insert, in cross-section;

FIG. 5 shows the tool shank with the braced fastening pin of the cuttinginsert, in cross-section;

FIG. 6 shows an alternative embodiment of a rotary cutting tool composedof a tool shank and a cutting insert;

FIG. 7 shows the tool shank of the rotary cutting tool of FIG. 6;

FIG. 8 shows the tool shank of FIG. 7 in detail;

FIG. 9 shows the cutting insert of the rotary cutting tool of FIG. 6;and

FIG. 10 shows the cutting insert of FIG. 9 in detail.

DESCRIPTION OF EMBODIMENT OR EMBODIMENTS

Identical parts are provided with the same reference number in alldrawings.

FIGS. 1 to 3 show a perspective view of a cutting element or cuttinginsert 1 and a drill shank or tool shank 2 of a rotary cutting tool 3 inthe form of a drilling tool. A recessing, milling or reaming tool, forexample, may be similarly configured. Especially hard metal, cermet,ceramic and HSS, either coated or uncoated, are the materials used forthe cutting insert 1. It is possible to provide a cutting insert 1 withPCD or CBN. The cutting insert 1 is finished either conventionally bypolishing, for example, or by means of the so-called “metal injectingmolding” (MIM) method. The cutting insert 1 is inserted into the toolshank 3 at the tip 4 of the shank. Both for inserting and releasing thecutting insert 1 from the tool shank 2 a key (not shown) is used. Thedirection of rotation of the tool is identified by D, the tool or drillaxis is identified by A. The tool shank 2, advantageously made of steelor hard metal, is provided with two twisted chucking grooves or chipflutes 5 that extend from a tool seat (not shown) to the tip 4 of theshank. As an alternative to the two twisted chucking grooves 5, the toolshank 2 can also be provided with a different quantity of straight ortwisted chucking grooves. Two recesses 6 bordering on the chuckinggrooves 5 at the tip 4 of the shank each have a rim 7 that extendsperpendicular to the tool axis A and a bearing surface 8 extending at anincline relative to the tool axis A. The bearing surface 8 delimits alimb 9 on the circumference of the tool shank 2. When the tool 3 isassembled, a bearing surface 10 of a wing 11 of the cutting insert 1rests against the bearing surface 8 of the limb 9. The bearing surfaces8, 10 are inclined relative to the tool axis A in such a way that thecutting insert 1 is pulled against the tool shank 2 when the rotarycutting tool 3 rotates in the direction of rotation D of the tool. Theinclination of the bearing surfaces 8, 10 relative to the tool axis Acorresponds to the angle of twist of the chucking grooves 5. Therefore,the wings 11 of the cutting insert 1 have a constant width B along thetool axis A over virtually the entire height H.

The wings 11 of the cutting insert 1 rise slightly above the tool shank2 at the tip 4 of the shank. The limbs 9 are not covered by the cuttinginsert 1 at the tip 4 of the shank. The diameter D_(s) of the cuttingelement of the cutting insert 1 is slightly greater than the diameterD_(w) of the tool shank. The transition between the rim 7 of the toolshank 2 and the adjacent bearing surface 8 of the limb 9 is rounded soas to prevent mechanical stress peaks. The shank-end narrow side 12 ofthe cutting insert 1 rests against the rim 7. When the cutting insert 1is inserted in the tool shank 2 and before it is tightened, said bearingsurface 8 is not available for positioning the cutting insert 1. Inorder to define the position of the cutting insert 1 before it istightened a guiding step 13 is provided on the tool shank 2 adjacent tothe limbs 9 and a corresponding guiding step 14 is provided on thecutting insert 1. A fastening pin 15 borders on the guiding step 14 ofthe cutting insert 1. Said pin is accommodated in a location opening 16in the tool shank 2. The recess 6 provided on the tip 4 of the shank andon the tool circumference combined with the adjacent location opening 16forms a space for inserting the cutting insert 1, including thefastening pin 15, in the tool shank 2. The fastening pin 15 has abeveled edge 17 so as to facilitate insertion into the location opening16. The location opening 16 is disposed concentric to the tool axis Aand has a circular cross-section, while the cross-section may vary alongthe tool axis A. Alternatively, the cylindrical location opening 16 mayalso be configured conical, especially tapering downward, which meansaway from the tip 4 of the shank. In the reverse case, where a locationopening 16 conically widens downward, the cutting insert 1 is furthersecured against falling out or being pulled out of the tool shank 2. Thelocation opening 16 is open to the chucking grooves 5 so that it is easyto insert the cutting insert 1 in the tool shank 2 in any case. Thecutting insert 1 can easily be centered with any configuration of thefastening pin 15 and the location opening 16.

FIGS. 4 and 5 show the tool shank 2 in cross-section with the fasteningpin 15 inserted in the location opening 16, both in released and bracedposition. According to this advantageous embodiment, the fastening pin15 has a slightly elliptical cross-section.

As a result of the elliptical cross-section, the fastening pin 15 hassome play when it is inserted in the location opening 16. By rotatingthe cutting insert 1 by approx. 45°, the fastening pin 15 is braced inthe location opening 16. The fastening pin 15 is laterally cut in such away that it adapts to the form of the chucking grooves 5 when it isbraced. Instead of the elliptical cross-section, the fastening pin 15and/or the location opening 16 can also have another, non-circularcross-section by means of which the fastening pin 15 can be braced inthe location opening 16 of the tool shank 2. Such cross-sectionalconfigurations are known, for example, in relation to a bracing meansaccording to DE 199 45 097 A1 for connecting a shaft with a hub so as tobe rotation-proof and thrust-proof.

The slightly elliptical configuration of the cross-section of thefastening pin 15 can be achieved both with a cylindrical basic form ofthe fastening pin 15 and with a conical configuration of the locationopening 16 and the fastening pin 15. In the case where the locationopening 16 conically widens downward and at the same time, the fasteningpin 15, which is also conical overall, has an elliptical cross-sectionan axial force is produced when the fastening pin 15 is rotated into thelocation opening 16. Said axial force pulls the fastening pin 15 intothe location opening 16 and thus supports the axial force holding thecutting insert 1 on the tool shank 2 by means of the bearing surfaces 8,10.

FIGS. 6 to 10 illustrate an advantageous alternative embodiment of arotary cutting tool in the form of a drilling tool 3 and the tool shank2 or the cutting insert 1 of the drilling tool 3. In this case, the limb9 of the tool shank 2 is provided with a supplemental bearing surface 8a in addition to the bearing surface 8. Similarly, the wing 11 of thecutting insert 1 is provided with a supplemental bearing surface 10 athat corresponds to the supplemental bearing surface 8 a of the toolshank 2. Otherwise, the configuration of the rotary cutting tool 1 inaccordance with said second exemplary embodiment substantiallycorresponds to the configuration of the first exemplary embodiment. Bothsupplemental bearing surfaces 8 a, 10 a are inclined relative to thetool axis A opposite the bearing surfaces 8, 10. Between the bearingsurface 10 and the supplemental bearing surface 10 a of the wing 11, atransitional area 18 extends approximately parallel to the tool axis A.

In contrast, the bearing surface 8 is connected to the supplementalbearing surface 8 a of the limb 9 merely by a rounding 19. Therefore,when the cutting insert 1 is inserted in the tool shank 2, thetransitional area 18 does not rest on the tool shank 2. Therefore, therotation of the cutting insert 1 relative to the tool shank 2 when thetool 3 is assembled is not limited by the transitional area 18, butmerely by the bearing surfaces and supplemental bearing surfaces 8, 10,8 a, 10 a.

The bearing surface 8 of the limb 9, relative to the tool axis A,extends over a height of contact H_(a). The height over which thesupplemental bearing surface 8 a extends is called the counter-height ofcontact H_(g). The amount of the height of contact H_(a) exceeds theamount of the counter-height of contact H_(g) by approx. 50%. With thetool axis A, the bearing surface 8 a encompasses an angle of contact α₁and the supplemental bearing surface 8 a encompasses a supplementalangle of contact α₂. The amount of the supplemental angle of contact α₂is less than the amount of the angle of contact α₁. In the illustratedexemplary embodiment, the angle of contact α₁ is 30° and thesupplemental angle of contact α₂ is 20°. In addition to the lesserheight of the supplemental bearing surface 8 a compared to the bearingsurface 8, said difference is also a reason why the axial force pullingthe cutting insert 1 away from the tool shank 2 by the inclination ofthe supplemental bearing surface 8 a and the corresponding supplementalbearing surface 10 a of the cutting insert 1 is lower than the oppositeaxial force based on the inclination of the bearing surfaces 8, 10.Therefore, when a work piece is machined with the tool 3, a resultingremaining force pulls the cutting insert 1 against the tool shank 2.

By the inclining supplemental bearing surface 8 a of the limb 9 oppositethe bearing surface 8, the tool shank 2 is reinforced in the transitionbetween the limb 9 and the adjacent region of the tool shank 2, which isespecially highly stressed by cutting. At the same time, the stabilityof the cutting insert 1 is not negatively affected by the supplementalbearing surface 10 a on its wing 11. Also, the possibility of easilyinserting and removing the cutting insert 1 from the tool shank 2 is notaffected by the supplemental bearing surfaces 8 a, 10 a.

One feature or aspect of an embodiment is believed at the time of thefiling of this patent application to possibly reside broadly in a rotarycutting tool composed of a tool shank with at least one chucking grooveor chip flute and an exchangeable cutting insert with a recess foraccommodating the cutting insert at the tip of the shank and in the wallof the chucking groove delimited on the shank-end by a rim against whichthe shank-end narrow side of the cutting insert rests and the cuttinginsert is provided with a fastening pin that is accommodated in alocation opening of the tool shank, which is concentric relative to thetool axis, characterized in that the tool shank, on its circumference,is provided with a limb with a bearing surface bordering on thecircumference of the tool shank and inclined relative to the tool axisand corresponding to a likewise inclined bearing surface on a wing ofthe cutting insert, where the orientation of the inclination of thebearing surfaces corresponds to the direction of rotation of the tool,and the cutting insert only partly covers the tip of the tool shank.

Yet another feature or aspect of an embodiment is believed at the timeof the filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that the diameter of the cuttingelement is greater than the diameter of the tool shank.

Still another feature or aspect of an embodiment is believed at the timeof the filing of this patent application to possibly reside broadly in arotary cutting tool, characterized by a guiding step on the tool shankand a corresponding guiding step on the cutting insert.

A further feature or aspect of an embodiment is believed at the time ofthe filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that the bearing surfaces,relative to the tool axis, have an angle of contact of at least 15° andat most 60°.

Another feature or aspect of an embodiment is believed at the time ofthe filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that the angle of twist of thechucking groove corresponds to the angle of contact of the bearingsurfaces.

Yet another feature or aspect of an embodiment is believed at the timeof the filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that the fastening pin issubstantially cylindrical.

Still another feature or aspect of an embodiment is believed at the timeof the filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that the fastening pin issubstantially conical.

A further feature or aspect of an embodiment is believed at the time ofthe filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that the fastening pin has anelliptical cross-section.

Another feature or aspect of an embodiment is believed at the time ofthe filing of this patent application to possibly reside broadly in arotary cutting tool, characterized by a supplemental bearing surface onthe limb which is inclining relative to the tool axis opposite thebearing surface of the limb and corresponding with a supplementalbearing surface on the wing of the cutting insert.

Yet another feature or aspect of an embodiment is believed at the timeof the filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that the bearing surface on thewing of the cutting insert is facing the tip of the shank and thesupplemental bearing surface on the wing of the cutting insert is facingthe fastening pin.

A further feature or aspect of an embodiment is believed at the time ofthe filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that the supplemental bearingsurfaces, relative to the tool axis, have a supplemental angle ofcontact in the range between −10° and −60°.

Yet another feature or aspect of an embodiment is believed at the timeof the filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that the amount of the angle ofcontact of the bearing surfaces exceeds the amount of the supplementalangle of contact of the supplemental bearing surfaces.

Still another feature or aspect of an embodiment is believed at the timeof the filing of this patent application to possibly reside broadly in arotary cutting tool, characterized in that a height of contact overwhich the bearing surface of the limb extends relative to the tool axisis greater than a counter-height of contact over which the supplementalbearing surface of the limb extends relative to the tool axis.

Another feature or aspect of an embodiment is believed at the time ofthe filing of this patent application to possibly reside broadly in acutting insert for a rotary cutting tool.

The purpose of the statements about the technical field is generally toenable the Patent and Trademark Office and the public to determinequickly, from a cursory inspection, the nature of this patentapplication. The description of the technical field is believed, at thetime of the filing of this patent application, to adequately describethe technical field of this patent application. However, the descriptionof the technical field may not be completely applicable to the claims asoriginally filed in this patent application, as amended duringprosecution of this patent application, and as ultimately allowed in anypatent issuing from this patent application. Therefore, any statementsmade relating to the technical field are not intended to limit theclaims in any manner and should not be interpreted as limiting theclaims in any manner.

A further feature or aspect of an embodiment is believed at the time ofthe filing of this patent application to possibly reside broadly in arotary cutting tool that is composed of a tool shank with at least onechucking groove or chip flute and one exchangeable cutting insert. Atthe tip of the shank as well as in the wall of the chucking groove, arecess for accommodating the cutting insert is provided and delimited onthe shank end by a rim against which the shank-end narrow side of thecutting insert rests. The cutting insert comprises a fastening pin whichis accommodated in a location opening of the tool shank that isconcentric to the tool axis. The tool shank, on its circumference, has alimb with a bearing surface that is inclined relative to the tool axisand that corresponds to a likewise inclined bearing surface on a wing ofthe cutting insert. The orientation of the inclination of the bearingsurfaces corresponds to the direction of rotation of the tool. Theinclination of the bearing surfaces produces an axial force that retainsthe cutting insert on the tool shank.

Another feature or aspect of an embodiment is believed at the time ofthe filing of this patent application to possibly reside broadly in arotary cutting tool, such as a drill, having a central longitudinalaxis, said rotary cutting tool comprising: a tool shank comprising atleast one chip flute; said tool shank having a first end portion beingconfigured to be inserted into a tool holder; said tool shank having asecond end portion disposed opposite said first end portion; said secondend portion comprising a replaceable cutting insert being configured tocut an object; said second end portion comprising a recess beingconfigured and disposed to receive and hold said cutting insert; saidrecess comprising a central opening disposed concentric to said centrallongitudinal axis; said cutting insert comprising a fastening pin beinginserted and retained in said central opening; said second end portioncomprising a limb disposed about said recess; said limb having an outersurface, an inner surface, and an end face, said inner surface forming aportion of said recess; said limb comprising a rim surface disposedbetween and transverse to said outer surface and said inner surface, anddisposed a distance from said end face; said cutting insert comprising asupport surface disposed about said fastening pin; said support surfacebeing configured and disposed to rest against said rim surface; saidlimb comprising a bearing surface disposed between and transverse tosaid outer surface and said inner surface; said bearing surface beinginclined at an angle with respect to said central longitudinal axis andbeing disposed between said rim surface and said end face; said cuttinginsert comprising an inclined bearing surface corresponding to saidinclined bearing surface of said limb; each of said inclined bearingsurfaces being inclined toward the direction of rotation of the rotarycutting tool to hold said cutting insert in said recess during cuttingof an object; said second end portion having a tip; and said cuttinginsert being configured and disposed to form only a portion of said tip.

Yet another feature or aspect of an embodiment is believed at the timeof the filing of this patent application to possibly reside broadly in areplaceable drill cutting insert for use in a drill having a centrallongitudinal axis and at least one chip flute, said cutting insertcomprising: an elongated portion being configured to be inserted intoand retained in a central opening in a shank of a drill; an inclinedbearing surface being configured to engage with a corresponding inclinedsurface in a peripheral side of a recess of a shank of a drill; and saidinclined bearing surface being inclined at an angle to hold said cuttinginsert in a recess of a shank of a drill during drilling of an object;and said cutting insert being configured to be disposed in a drill toform only a portion of a cutting end of a drill.

The appended drawings in their entirety, including all dimensions,proportions and/or shapes in at least one embodiment, are accurate andare hereby included by reference into this specification.

The background information is believed, at the time of the filing ofthis patent application, to adequately provide background informationfor this patent application. However, the background information may notbe completely applicable to the claims as originally filed in thispatent application, as amended during prosecution of this patentapplication, and as ultimately allowed in any patent issuing from thispatent application. Therefore, any statements made relating to thebackground information are not intended to limit the claims in anymanner and should not be interpreted as limiting the claims in anymanner.

All, or substantially all, of the components and methods of the variousembodiments may be used with at least one embodiment or all of theembodiments, if more than one embodiment is described herein.

The purpose of the statements about the object or objects is generallyto enable the Patent and Trademark Office and the public to determinequickly, from a cursory inspection, the nature of this patentapplication. The description of the object or objects is believed, atthe time of the filing of this patent application, to adequatelydescribe the object or objects of this patent application. However, thedescription of the object or objects may not be completely applicable tothe claims as originally filed in this patent application, as amendedduring prosecution of this patent application, and as ultimately allowedin any patent issuing from this patent application. Therefore, anystatements made relating to the object or objects are not intended tolimit the claims in any manner and should not be interpreted as limitingthe claims in any manner.

The summary is believed, at the time of the filing of this patentapplication, to adequately summarize this patent application. However,portions or all of the information contained in the summary may not becompletely applicable to the claims as originally filed in this patentapplication, as amended during prosecution of this patent application,and as ultimately allowed in any patent issuing from this patentapplication. Therefore, any statements made relating to the summary arenot intended to limit the claims in any manner and should not beinterpreted as limiting the claims in any manner.

The corresponding foreign and international patent publicationapplications, namely, Federal Republic of Germany Patent Application No.102 07 257.4, filed on Feb. 21, 2002, having inventors BernhardBORSCHERT, Dieter MUHLFRIEDEL, and Jurgen SCHWAGERL, and DE-OS 102 07257.4 and DE-PS 102 07 257.4, and International Application No.PCT/EP03/01526, filed on Feb. 15, 2003, having WIPO Publication No.WO03/070408 and inventors Bernhard BORSCHERT, Dieter MOHLFRIEDEL, JurgenSCHWAGERL, Ruy FROTA DE SOUZA, FILHO, Michael D. SHULTZ, and Michael R.MCCORMICK, as well as their published equivalents, and other equivalentsor corresponding applications, if any, in corresponding cases in theFederal Republic of Germany and elsewhere, are hereby incorporated byreference as if set forth in their entirety herein.

The description of the embodiment or embodiments is believed, at thetime of the filing of this patent application, to adequately describethe embodiment or embodiments of this patent application. However,portions of the description of the embodiment or embodiments may not becompletely applicable to the claims as originally filed in this patentapplication, as amended during prosecution of this patent application,and as ultimately allowed in any patent issuing from this patentapplication. Therefore, any statements made relating to the embodimentor embodiments are not intended to limit the claims in any manner andshould not be interpreted as limiting the claims in any manner.

The purpose of the title of this patent application is generally toenable the Patent and Trademark Office and the public to determinequickly, from a cursory inspection, the nature of this patentapplication. The title is believed, at the time of the filing of thispatent application, to adequately reflect the general nature of thispatent application. However, the title may not be completely applicableto the technical field, the object or objects, the summary, thedescription of the embodiment or embodiments, and the claims asoriginally filed in this patent application, as amended duringprosecution of this patent application, and as ultimately allowed in anypatent issuing from this patent application. Therefore, the title is notintended to limit the claims in any manner and should not be interpretedas limiting the claims in any manner.

The abstract of the disclosure is submitted herewith as required by 37C.F.R. §1.72(b). As stated in 37 C.F.R. §1.72(b):

A brief abstract of the technical disclosure in the specification mustcommence on a separate sheet, preferably following the claims, under theheading “Abstract of the Disclosure.” The purpose of the abstract is toenable the Patent and Trademark Office and the public generally todetermine quickly from a cursory inspection the nature and gist of thetechnical disclosure. The abstract shall not be used for interpretingthe scope of the claims.

Therefore, any statements made relating to the abstract are not intendedto limit the claims in any manner and should not be interpreted aslimiting the claims in any manner.

What is claimed is:
 1. A tool shank for use with a cutting insert in arotary cutting tool, the tool shank comprising: a body having, andadapted to be rotated about, a central longitudinal tool axis, the bodyhaving a tip portion structured to receive at least a portion of thecutting insert therein; a pair of chip flutes formed in the body; and apair of recesses, each recess bordering a respective chip flute, eachrecess having: a rim portion extending perpendicular to the tool axis,and a bearing surface extending at an incline relative to the tool axis,wherein each rim portion is adapted to engage a corresponding surface onthe cutting insert, and wherein each bearing surface is adapted toengage a corresponding bearing surface on the cutting insert in a mannersuch that the cutting insert is pulled against the body when the rotarycutting tool is rotated about the tool axis.
 2. The tool shank of claim1, wherein each chip flute is disposed at a twist angle and wherein eachbearing surface is inclined at an angle corresponding to the twistangle.
 3. The tool shank of claim 1 wherein the body comprises alocation opening extending into the body from the tip and wherein thelocation opening is adapted to receive a fastening pin extending fromthe cutting insert.
 4. The tool shank of claim 3 wherein the locationopening is disposed concentric to the tool axis and has a circularcross-section when viewed along the tool axis.
 5. The tool shank ofclaim 4 wherein the location opening is generally cylindrical in shape.6. The tool shank of claim 4 wherein the location opening is conical inshape.
 7. The tool shank of claim 3 wherein the location opening isdisposed concentric to the tool axis and has a non-circularcross-section when viewed along the tool axis.
 8. The tool shank ofclaim 1 wherein each recess further comprises a supplemental bearingsurface inclined relative to the tool axis opposite the respectivebearing surface, wherein each supplemental bearing surface is adapted toengage a corresponding supplemental bearing surface on the cuttinginsert.
 9. The tool shank of claim 8 wherein each recess furthercomprises a transitional area disposed between the respective bearingsurface and supplemental bearing surface.
 10. The tool shank of claim 9wherein the transitional area comprises a rounding.
 11. The tool shankof claim 9 wherein the transitional area is adapted to not contact thecutting insert when the cutting insert is received in the tip portion ofthe body.
 12. The tool shank of claim 8 wherein: each bearing surface,relative to the tool axis, extends over a first height of contact; eachsupplemental bearing surface, relative to the tool axis, extends over ssecond height of contact; and the first height of contact exceeds thesecond height of contact by approximately 50%.
 13. The tool shank ofclaim 8 wherein: each bearing surface is inclined relative to the toolaxis at a first angle; and each supplemental bearing surface is inclinedrelative to the tool axis at a second angle less than the first angle.14. The tool shank of claim 13 wherein the first angle is about 30° andthe second angle is about 20°.
 15. The tool shank of claim 1 whereineach bearing surface is inclined at an angle of at least 15° and at most60° with respect to the tool axis.
 16. The tool shank of claim 8 whereineach supplemental bearing surface is inclined at an angle in the rangeof between 10° and 60° with respect to the tool axis.